Chart for teaching addition



(No Model.) 2 Sheets-Sheet 1.

A. L. GILLIS.

CHART FOB. TEACHING ADDITION. No. 416,593. W Patented Dec. 3,18%.

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(No Model.) 2 Sheets Sheet' 2.

A. L. GILLIS. CHART FOR TEACHING ADDITION.

No. 416,593. Patented Den. 3, 1889.

Fig. 2.

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U ITED STATES PATENT QFFICE.

ARTHUR Ii. GILLIS, OF MOUNT PLEASANT, IOVA.

.CHART FOR TEACHING ADDITION.

SPECIFICATION forming part of Letters Patent No. 416,593, dated December3, 1889.

Application filed September l9 1889. Serial No. 324,390. (No model.)

.lowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains to'make and use the same, reference being had to the accompanyingdrawings, and to letters or figures of reference marked thereon, whichform a part of this specification.

Myinvention relates to charts for teaching addition; and it consists inthe improved device hereinafter described and set forth, whereby asimple and efficient arrangement is provided for the purpose stated.

In the accompanying drawings, forming a part of this specification,Figure 1 is a front view of a chart embodying my improvements. Fig. 2 isa vertical longitudinal section of said chart. Fig. 3 is a detail viewof a section of the slide for concealing the sum of the several columns.

The body of the chart consists of the main rectangular section A, whichis provided with a series of openings a. At the top of said chart atransverse wooden strip 1) is located, which serves to stiffen and bracethe chart at such point, and may be arranged to present an ornamentalmolding and serve as a means for strengthening or suspending the chart.A series of vertical strips B are inserted through the bottom of thesection A, so that each of a series of numerals on each strip may bedisplayed or exhibited through one of the openings of the section. Thestrips B are each of such length that they extend beyond the bottom andtop edges of said section A. to enable them to be readily drawn ineither direction by hand to shift or change the display of numeralsthrough the openings a in the section A. It will be noted that theopenings a in each horizontal series alternate with those of the nextseries above and below.' The intermediate or dead spaces 0 on the faceof the section A are provided with certain numerals, as indicated in thedrawings. The

alternating feature of the openings a does not occur in the matter ofthe bottom series of openings, where they are extended continuouslyacross the section, so that an opening is provided for each verticalcolumn or strip. Between each pair of openings of the bottom series themain section A is provided with a pair of vertical slots to enable thetransverse slide 0 to be looped therethrough, the said slide being mostclearly shown in Fig. 3, and contains a series of openings (1, thusenabling the slide to be shifted transversely in either direction toeither display or conceal the figures of the several strips in saidbottom series of openings.

To designate the several vertical columns or series the section A hasupon its face, beneath the strip b, a number of alphabetical characters,which, as shown, extend from A to H, inclusive, and each individuallydesignates one of the several columns. It will be noted by reference toFig. 1, and more particularly by the lower exposed portion of the stripin the column II, that each of said strips in its several divisionsthroughout is provided alternately with numerals of greater and lessvalue, the arrangement Joeing such that when any one of the strips is soadjusted in its column that two of its figures of less value aredisplayed through the opening a of that column said displayed figures,in connection with the figures in the dead-spaces C of the section,willrepresent a total indicated by the number of the strip exhibited throughthe lower opening of the section. Thus it will be seen in Fig. 1 thatfigures 5 and 3 appear on the respective dead-spaces of the section,while the figures 2 and 3 on the strip are exhibited through theopenings a therein, which collectively amount to the sum of 13, exposedthrough the lower opening of the section.

In use the teacher may adjust the several strips to obtain a differenttotal in each column, and before exposing the same to the pupils orscholars shift the transverse slide 0, so that the totals are allconcealed, and different scholars may be required to compute the totalnumber of the individual columns by selecting said columns withreference to their alphabetical designation. Two or more columns may beused for asingle ex- ICO ample, and the produetcan be ascertained bysimply adding the two products of each column, which are indicatedtogether. It will therefore be seen that the device is very simple andinexpensive and highly serviceable in teaching scholars to rapidly addor calculate the sum total of aseries of numbers.

I claim 1. The combination, with a main section A, having a number ofvertical openings and dead-spaces intermediate of the same provided withnumerals, ofv a series of vertical strips looped through said sectionand provided with numerals of alternating greater and less value toexpose the same through the opening in the section and indicate at thebottom opening in the section the total number of figures in theopenings and dead-spaces above, substantially as set forth.

2. The combination, with the main section provided with anumber ofopenings arranged in vertical series and relatively alternating, asdescribed, of a number of strips looped through said section andprovided with alternating numbers of greaterand less value and adaptedto be exposed through the openings in said section, numerals or figureslocated in the dead-spaces of the section, and atransverse slide adaptedto conceal the figures of greater value exposed through the bottom se-

